Hydraulic expander



Oct. 11, 1960 R. E. ROPER ETAL HYDRAULIC EXPANDER 3 Sheets-Sheet 1 FiledMay 31 INVENTORS. 1'. R01:

KHLPH Oct. 11, 1960 R. E. ROPER ETAL 2, 5

HYDRAULIC EXPANDER Filed May 31, 1957 5 Sheets-Sheet 3 C-I\ Q i &iv y III U U INVENTORS.

United States Patent HYDRAULIC EXPANDER Ralph E. Roper and Eugene K.Fike, Indianapolis, Ind., assignors, by mesne assignments, to WallaceExpanding Ilillachines, Inc., Indianapolis, Ind., a corporation of dianaFiled May 31, 1957, Ser. No. 662,860

1 Claim. (Cl. 113-48) This invention relates generally to metal workingtools and more particularly it relates to a mechanism especially adaptedfor forming cylindrical or rectangular metallic shapes from weldedmetallic cylinders of sheet metal.

In the manufacture of sheet metal cabinets, washing machine casings,electrical drier casings and other products of like nature, it has beenconventional practice to form the casings of this type one or two sidesat a time and then to weld the several sides together to form acomplete, relatively rigid, casing. This has been necessary particularlywhere it is desired to form a casing having decorative or functional,recessed, or expanded surface sections which normally require flow ofmetal during the forming process.

Heretofore it has been necessary to fabricate a casing of the typedescribed from individual sheets of sheet metal particularly wherecomplex shapes are being formed. Where attempts have been made to formcomplex shapes from a preformed metallic cylinder, the

metal would tear or wrinkle, thereby making it impossible to produce adesired shape in a single forming operation. Also, such shapes would nothave a permanent, true, circular or rectangular form.

The principal object of this invention is to provide a metal workingmachine adapted to expand a welded cylinder of sheet metal into apermanently set, true, rectangular or cylindrical shape having complexprojecting or recessed decorative or surface sections.

Another object of this invention is to provide a machine tool adapted toform metallic shapes of the type described in a single cycle ofoperation.

In. accordance with this invention, there is provided a metal workingmachine comprising an expandable die mechanism adapted to receivethereon a sheet metal cylinder, cam means disposed within said die andoperable for expanding it to stretch said cylinder, and an externalcontracting die including means for contracting it into metal formingcontact with said expanding die while the metal of said cylinder isbeing stretched.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claim:

Fig. 1 is a top plan view of the metal working machine as provided inaccordance with this invention;

Fig. 2 is a cross-section taken on line 2-2 of Fig. 1; and

Fig. 3 is a cross-section taken on line 3-3 of Fig. 2 and showing thedies in retracted position.

This invention comprises a metal working machine having a base 10, whichmay be supported at floor level by means of stanchions 11 disposed belowfloor level. An expandable die mechanism is supported on the base andcomprises a plurality of driver sections 14 arranged about a commoncenter, each of which is formed to have a generally arcuate external diesurface 15, and a pair of internal inclined cam surfaces 16. Where it isdesired to form in the external surface of a sheet 2,955,556 PatentedOct. 11, 1960 metal cylinder 17 a protruding surface section such as 18,one or more of the dies 16 may be provided with a pad 20 which providesthe external die surface adapted to form the protruding section 18.

As shown in Fig. l, the expanding die mechanism may include fiveso-called driver die sections spaced apart from one another andoperatively engaging the driven die sections 22 disposed betweenadjacent driver sections. The external surfaces of sections 22 aregenerally arcuate in form and are so designed as to conform with thearcuate surfaces 15 of the driver sections 14 so that the complete diemechanism presents a continuous cylindrical surface when the mechanismis in its fully expanded position. This feature of the invention isimportant in that it prevents any marking or deforming of the sheetmetal cylinder during its forming operation. Driven sections 22 includeinclined cam surfaces 23 which cooperate with inclined cam surfaces 24of driver sections 14 whereby sections 22 are cammed from their innerpositions indicated at 25 (Fig. l) to their outer positions as indicatedat 26- in Fig. 1. Die sections 14 and 22 may be undercut as at 27 toform a rim onv cylinder 17.

The die sections 14 annd 22 rest on and slide on the upper surfaces ofthe base 10 and are positioned and supported in operative relation withone another by means of an external housing structure comprising in partan upper housing member 28 having a cover 29 clamped in position bymeans of the bolts 30 threaded into the base 10 at 32 and havingenlarged spacer sections 33. Cooperating with housing 28 and the base 10is a centrally disposed shaft 34 having fixed thereto a die operatingcam 35 having cam surfaces 36 which mate with cam surfaces 16 of driversections 14. Shaft 34 is supported at its top end in the bearing andseal 37, mounted in cover 29, and includes a cap 38 which extends intobearing and sealing relation with member 37. The lower end of shaft 34is supported in a hearing and seal 39 which in turn is supported fromthe base 10 by means of a collar 40 bolted to base 10 by the stud 41.Shaft 34 may form the extension of a hydraulic piston (not shown) whichoperates in hydraulic cylinder 42 extending upwardly to the base 10 andsealed and secured thereto by means of collar member 43 bolted to base10 by machine screws 44.

The die members 14 and 22 are confined or restrained into engagementwith cam 35 by means of retraction springs 46 and 47, springs 46 beingnested within slots 48 in base 10 and operatively associated with diemembers 14 and 22 by means of L-shaped guides 49. Similarly, retractionsprings 47 are nested within slots 50 formed in the lower surface ofhousing 28 and operatively associated with the die members 14 and 22 bymeans of the L-shaped guides 51.

From the foregoing description it will be apparent that upward movementof shaft 34 and cam 35 will permit retraction of die members 14 and 22under the control of the retraction springs 46 and 47, and downward movement will provide expansion of the die mechanism through the action ofthe cooperating cam surfaces 16 and 36.

Outer dies surround the expanding die and are positioned by means of anexternal housing 53. The outer dies include arcuate sections 54 havingdie surfaces which mate with the outer surfaces of inner dies 16 and 22and cam surfaces 55 and 56 which cooperate with outer cams 58 having camsurfaces 59 and 60. Outer cams 58 may be in the form of a completeannulus or divided into sections and may be operated by one or morehydraulic rams 62 having shafts 63 threaded into cams 58 as shown at 64.

For retracting the outer dies 54 there is provided a mechanismconsisting of the stud bolts 66 threaded into die 54 at 67 andcompressing springs 68 within bores 69 in housing 53. When cam 58 isoperated to move the dies 54 into engagement with the sheet metalcylinder 18, springs 68 are compressed so that they function to drawdies 54 outwardly when cam 58 moves to its lowermost position.

For ejecting cylinder 17 after it has been formed by the dies, there isprovided an ejector consisting of one or more hydraulic rams 71 attachedin any suitable manner to the lower surface of the base and including ashaft 72 projecting upwardly in alignment with the space between innerdies 14, 22 and outer dies 54. The ram 71 may be used both for loweringcylinder 17 into position for forming, and elevating cylinder 17 afterit is formed to a position where it may be removed from the machineeither manually or by means of a hoist.

In operation it may be assumed that shaft 34 and cam 35 are in theiruppermost positions and the die sections 14 and 22 are in theirretracted positions. Similarly, cam 58 is in its lowermost positionwhereby die sections 54 are retracted to their outermost positions. Thisleaves a space at 70 between the inner and outer die sections into whicha welded cylinder 17 of sheet metal may be dropped.

In order to form cylinder 17 into a relatively rigid cylindrical casing,the piston in cylinder 42-may be controlled to draw the shaft 34downwardly whereby cam 35 drives the driver die sections 14 in anoutward direction. As shown in Fig. 3, the driven die sections 22project outwardly beyond driver sections 14. It will be apparent fromthe geometrical relationship between die sections 14 and 22 that theouter surfaces of driven die section 22 project outwardly of the outersurfaces of driver sections 14 until driver sections 14 reach theiroutermost radial positions to form a continuous cylindrical surface.

Before die sections 14 reach their outermost positions, the driven diesections 22 will engage portions of and stretch the cylinder 17, and theundercut portion 27 of sections 14 and the similar undercut portion ofsection 22 will begin forming sections of a rim on cylinder 17. As allof the die sections move outwardly, the metal of cylinder 17 isstretched and can flow to prevent tearing or fracture. During thestretching process, the die sections 22 form sections of a rim oncylinder 17 and then sections 14 will have begun to form intermediatesections of the rim while all the metal is still stretching and in thismanner a continuous, smooth and unwrinkled or unbroken rim may be formedon cylinder 17.

The operation of the rams 62 may be timed with relation to the operationof cam 35 to be moved upwardly and move outer die sections 54 intocontact with cylinder 17 while it is being stretched by inner diesections 14 and 22. This has the effect of laying the metal of thecylinder 17 on to the protruding parts of dies 14 and 22 while the metalis being stretched by dies 14 and 22 At the same time outer dies 54 flowthe metal of cylinder 17 into any depressions in the die sections 14 and22 As a result of the cooperative stretching of cylinder 17 by the innerdie sections and the laying of metal on the protruding parts of the diesections, no tearing or wrinkling of cylinder 17 occurs and a rigidcasing member is formed in one continuous operation After the formingoperation is completed, the machine may be controlled to permit theouter dies to assume their outermost positions and to permit the innerdies to assume their innermost positions, thereby freeing the finishedcylinder 17. The ejector rams 71 may then be operated to elevate thecylinder 17 to a position where it may be lifted free of the machineFrom the foregoing description, it will be readily apparent that thisinvention provides a mechanism adapted to form cylindrical metallicshapes from welded metallic cylinders of sheet metal. The formingprocess eliminates a series of separate operations on separate pieces ofmetal and is effective in a single cycle of operation to form a casingmember which is relatively rigid and holds its shape.

While the invention has been disclosed and described in some detail inthe drawings and foregoing description, they are to be considered asillustrative and not restrictive in character, as other modificationsmay readily suggest themselves to persons skilled in this art and withinthe broad scope of the invention, reference being had to the appendedclaim.

The invention claimed is:

A metal forming device for forming a cylindrical metallic shapecomprising a base, a plurality of radially disposed, spaced, driver diesections slidably mounted at their lower ends on said base and eachhaving a die surface in the form of a vertical section of a cylinder,driven die sections disposed between said driver die sections and eachhaving a die surface in the form of a vertical section of a cylindercomplementing the adjacent die surfaces of said driver sections to forma complete cylindrical die surface, a cam slidably mounted centrally ofsaid driver die sections and having radially extending cam surfacesengaging each driver section, independent drive means for said cam, saiddriver and driven die sections having mutually cooperating cam surfaceswhereby movement of said centrally disposed cam moves all of said diesections outwardly to form a continuous cylindrical die surface, saidmutually cooperating cam surfaces being formed so that said driven diesections reach metal forming position prior to said driver die sections,a cover slidably engaging the upper ends of said die sections, springmeans engaging the upper and lower ends of said die sections and saidbase and cover for retracting s id die sections, outer die sectionssurrounding said cam-operated die sections each having die surfacesmating with the die surfaces of said cam-operated die sections, an outercasing surrounding said outer die sections, cam means operativelyassociated with said casing and said outer die sections for moving saidouter die sections into metal forming relation with said cam operateddie sections, and independent drive means for said cam means.

References Cited in the file of this patent UNITED STATES PATENTS284,440 Lamont Sept. 4, 1883 1,268,789 Bryant 2 June 4, 1918 1,453,647Waterman May 1, 1923 1,556,847 Kranz Oct. 13, 1925 1,625,854 Holt Apr.26, 1927 1,698,999 Hothersall Jan. 15, 1929 1,705,843 Walter Mar. 19,1929 2,198,873 Hinsdale -2 Apr. 30, 1940 2,458,587 Gogan Jan. 11, 1949

